The latest accusations in a complicated but intriguing political smear scandal could embroil not just France's former Prime Minister, Dominique de Villepin, but also its current Interior Minister, Michele Alliot-Marie.

Michele Alliot-Marie was defence minister under Jacques Chirac

Mr de Villepin has said he expects to be placed under formal investigation. He has been summoned for questioning later this month by investigating judges - but he strongly denies any wrongdoing.

A French newspaper has suggested Ms Alliot-Marie could also face legal action over her role in the alleged dirty tricks campaign against the man who is now her boss, Nicolas Sarkozy, before he became president.

The so-called Clearstream affair has cast suspicion on Mr de Villepin and the former President, Jacques Chirac.

Both were rivals of Mr Sarkozy and resented his presidential ambitions.

The allegations concerning Ms Alliot-Marie could cause a rift at the heart of the new government.

Testimony 'contradicted'

The events themselves date from 2003 to 2004, when Mr Sarkozy and others were falsely accused of holding secret accounts into which bribes were paid.

At no time did I ask anyone to investigate political figures, still less to compromise them

Dominique de VillepinFormer French PM

At the heart of the investigation is the extent to which the state's security services were manipulated to settle political scores.

According to Le Journal du Dimanche, new evidence appears to contradict Ms Alliot-Marie's testimony last year to the official inquiry.

She said she only became aware that Mr Sarkozy and other political figures were implicated in the alleged plot when their names appeared in the press in June 2004.

But documents are said to show that, as defence minister, she was informed at least some weeks beforehand, yet failed to alert her colleague.

Conspiracy claims

The claims are significant because they seem to add weight to allegations of a high-level plot to discredit Mr Sarkozy.

Gen Philippe Rondot was asked to investigate the affair in 2004

The latest evidence - retrieved from the memory of a computer belonging to a former intelligence chief, Gen Philippe Rondot - was examined by two investigating judges last week.

The same computer files contained notes of conversations alleging that when he was foreign minister, Mr de Villepin was told by President Chirac to denounce Mr Sarkozy.

They also implied that Mr de Villepin had suggested sending the Clearstream lists to a judge.

The magistrates have searched the premises of the former prime minister.

A raid on his home on Thursday was followed by a six-hour search of his office the following day.

Mr de Villepin has strongly denied the accusations.

"At no time did I ask anyone to investigate political figures, still less to compromise them", he told L'Est Republicain, a regional newspaper.

Rivalry

The new allegations do not constitute hard evidence against either Mr de Villepin or Ms Alliot-Marie.

They centre on notes of conversations between third parties, two of whom have already been formally accused in the Clearstream affair of either falsifying or circulating lists of names.

Nicolas Sarkozy and Dominique de Villepin were once political rivals

Nevertheless, the latest moves have given the long-running investigation a much-needed lift.

Judicial sources have said that they feel there is enough evidence for formal charges to be brought.

From the start, Mr Sarkozy has made it known he believes he was the victim of a concerted campaign to damage him.

Ms Alliot-Marie was once seen as a potential presidential challenger to Mr Sarkozy, but at the start of this year she decided to endorse him instead.

Her reward was the job of interior minister - an extremely high-profile post when it was occupied by Mr Sarkozy before he became president.

The recent twists in the Clearstream affair could revive tensions in their relationship and in the government, which both had hoped had been buried.